Wireless network and access point for a wireless network

ABSTRACT

Embodiments related to Wireless Networks and access points for a Wireless Network are described and depicted.

RELATED APPLICATIONS

This application is a Continuation Application of co-pending applicationSer. No. 11/861,289, which was filed on Sep. 26, 2007. The entirecontents of the co-pending Application are incorporated herein byreference.

BACKGROUND

Wireless local area networks (WLANs) are becoming increasingly importantin home, office or business applications as well as in otherapplications.

Various standards such as the IEEE 802.11 a/b/c/d/e/f/g/h/n standardshave been established for WLANs in order to allow wireless networkoperation. According to the various standards, wireless communicationmay be established using spread spectrum modulation, OFDM (orthogonalfrequency division modulation) or other modulation types. Typically, aninfrastructure wireless network includes one access point or a pluralityof access points to service wireless communication to one or a pluralityof client stations. An access point or an access point device is anentity that provides for client stations wireless access to distributionservices. An access point can for example be integrated or implementedin a gateway such as a DSL modem, a PON termination device, a router, acomputer device or a cable modem to provide for example wirelessconnectivity with one or multiple devices including mobile devices suchas laptops and personal digital assistants or stationary devices such aspersonal computers or consumer electronic devices at home. An accesspoint may also be part of a structure comprising a plurality of accesspoints which are interconnected using a wired or wireless distributionsystem to provide wireless communication coverage over a wider area forexample in offices or buildings.

A basic service set (BSS) is a set of stations that communicate witheach other. In an infrastructure basic service set, an access pointbuilds the central communication point such that all communication isrelayed through the access point. Stations that intend to join the basicservice set have to be associated with the basic service set. Typically,for example in the IEEE 802.11 standards, association requiresauthentication.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a basic network arrangement according to embodiments of thepresent invention;

FIG. 2 shows a block diagram according to an embodiment of the presentinvention;

FIG. 3 shows an exemplary method according to an embodiment of thepresent invention;

FIGS. 4 a to 4 b show an exemplary embodiment of the present invention;

FIGS. 5 a to 5 d show exemplary embodiments of the present invention;

FIGS. 6 a and 6 b show block diagrams of an architecture according toexemplary embodiments of the present invention;

FIGS. 7 a and 7 b show exemplary data transmission for a single BSSoperation;

FIGS. 8 a and 8 b show exemplary data transmission for a multiple BSSoperation; and

FIGS. 9 a-9 d show examples of coordination for two basic service sets.

DETAILED DESCRIPTION

The following detailed description explains exemplary embodiments of thepresent invention. The description is not to be taken in a limitingsense, but is made only for the purpose of illustrating the generalprinciples of embodiments of the invention while the scope of protectionis only determined by the appended claims.

In the various figures, identical or similar entities, modules, devicesetc. may be assigned the same reference number.

In the following, various embodiments will be described wherein anaccess point services concurrently two or more basic service sets in awireless local area network. The two or more basic service sets operatein different physical channels, i.e. use different frequencies for theRF transmission of data to the stations of a respective basic serviceset. As will be described later in more detail, the independent andconcurrent operation of at least two basic service sets by one accesspoint allows a flexible and dynamic configuration of the stations in thedifferent basic service sets which may for example be used to optimizethe data traffic to and from the various stations by the access point.

Referring now to FIG. 1, an exemplary WLAN network system 100 accordingto one embodiment includes an access point or access point device 102serving a first basic service set 104 a and a second basic service set104 b. The first and second basic service sets 104 a and 104 b eachinclude at least one client station or client station device 106assigned to the respective basic service set. The access point 102serves the first and second basic service sets 104 a and 104 bconcurrently and independently in different physical communicationchannels, i.e. the first and second channels used by the two servicesets operate at different center frequencies such that the usedfrequency channels do not overlap. Thus, the access point is capable ofsimultaneously, i.e. at a same time instant, transmitting or receivingfirst data signals for the first basic service set over the firstchannel via an antenna or a plurality of antennas and transmitting orreceiving second data signals for the second basic service set over thesecond channel via a another antenna or a plurality of other antennas.While FIG. 1 shows only one client station assigned to each of the basicservice sets, it is to be understood that the first and second basicservice sets 104 a, 104 b may include each a plurality of stations. Thestations 106 may be any known stations including mobile devices such aslaptops, mobile phones and personal digital assistants (PDAs) orstationary devices such as a personal computer or consumer electronicdevices, for example a TV, a set top box (STB), an audio/video systemetc. The various stations may have different transmission capabilitiesand may operate according to different standards. For example, in thefirst basic service set some of the stations may operate according tothe IEEE 802.11n standard while other stations may operate in a legacymode, for example according to the IEEE standards 802.11a, 802.11b or802.11g.

It is to be noted that in FIG. 1 and other figures explained below, theassignment of the multiple client station in multiple BSSs as shown byan oval zoning, is only a logical assignment or affiliation and not aspatial partitioning. Or in other words, the first and second basicservice sets 104 a and 104 b may cover a same area.

Furthermore, according to one embodiment the WLAN system 100 maycomprise a plurality of access points to form an extended service setwherein at least one of the plurality of access points is an accesspoint 102 as described above. The plurality of access points may beinterconnected by a distribution system which may be wired or wireless.The plurality of access points may form an extended service set to covera larger area and the distribution system may include Ethernettransmission capabilities.

As already mentioned, the access point 102 as shown in FIG. 1 is capableof servicing simultaneously multiple basic service sets. In order toallow the concurrent communication in the multiple basic service sets,the access point 102 comprises according to embodiments of the presentinvention multiple independent transmission/processing paths (MAC, PHYand RF chains). Thus, logically there are multiple MAC (medium accesscontroller) paths, each capable of operating independently from theother MAC paths, and multiple PHY paths, each capable to be operatedindependently from the other PHY paths and multiple RF engines, each RFengine capable of providing and receiving RF radiation independent fromthe other RF engines. As is known to a person skilled in the art, thePHY is the lowest layer in the 7-layer OSI model and the MAC is thelowest sub-layer of the next higher data link layer.

FIG. 2 shows an exemplary embodiment of an architecture which may beimplemented in the access point 102. As can be seen, first and secondtransmission/processing paths (pipelines) 202 a, 202 b are provided,each of the paths including a MAC entity 204 a, 204 b, a PHY entity 206a, 206 b coupled to the MAC entity 204 a, 204 b and an RF engine 208 a,208 b coupled to the PHY entity 206 a, 206 b. A BSS controller entity210 is coupled to both MAC entities 204 a, 204 b to perform controllingand management of the multiple basic service sets. If required, BSScontroller entity may provide coordination of the multiple MAC entitiesand/or PHY and/or RF engines. As used herein, controlling provided byBSS controller entity is to be interpreted in a broad sense and mayinclude managing functionalities for the different basic service setssuch as assigning and dynamically reassigning stations to the multiplebasic service sets serviced by the access point as well as bridgingfunctionalities to control data transfer to one of the MAC entities 204a, 204 b and controlling the operation mode of the MAC, PHY and RFengines for example controlling the physical transmission modes. Forexample, the BSS controller may control for each of the basic servicesets the channel coordination functions and contention window parametersto be used, whether to use aggregation and/or block acknowledgements offrames, the channel width (20 or 40 MHz) to be used, or whether to useMIMO techniques. As will be appreciated by the skilled person in theart, the BSS controller entity 210 may be directly provided in thehierarchical layer model above the MAC. Some of the functions providedby the BSS controller entity 210 may be located at other hierarchicallayers or may be provided by peripheral devices. The BSS controllerentity 210 is coupled to a data port interface which may be a gatewayinterface, a distribution system interface, a backbone interface or thelike. It is to be noted that the data port interface may be a singleinterface although logically two different basic service sets with twodifferent logical data streams are provided.

The BSS controller entity 210 as well as the MAC entity 204 a, 204 b orthe PHY entity 206 a, 206 b may be implemented in hardware, software,firmware or a combination of two or more of these. According toembodiments described below, the BSS controller entity and the MACentity and/or the PHY entity may share common resources such as aprocessor (CPU). The BSS controller entity, the MAC entities and the PHYentities may be integrated on a single chip whereas the RF engines maybe implemented on another chip. In other embodiments, the MAC entitiesand the PHY entities may be integrated on one chip whereas the BSScontroller may be provided by another chip, for example a gateway chip.

An exemplary operation will now be described with respect to FIG. 3.Referring to FIG. 3, a first client station is assigned at block 300 toa first basic service set BSS1 serviced by the access point 102. Atblock 310, a second client station is assigned to a second basic serviceset BSS2. Assignment of the stations to the first and second basicservice set may be based on specific criteria as will be outlined inmore detail below. The assignment of the first and second clientstations to the first and second basic service set may take placesimultaneously or at different time instances. As described above, theassignment may be provided by the BSS controller entity 210 describedwith respect to FIG. 2. The assignment of the first and second clientstation may further be part of or may be provided during the associationof the client station according to one of the IEEE 802.11 standards. Asis known to a person skilled in the art, authentication orpre-authentication may take place prior to the association of a clientstation with the access point. Furthermore, prior to the assignment to abasic service set, a client station may have been assigned to anotherbasic service set. For example, the second client station may have beenassigned prior to the assignment to the second basic service set in thefirst basic service set. Further, both the first and second clientstations may have been operated prior to the assignment to differentbasic service sets together in one single basic service set, for examplethe first basic service set. Authentication for a client station may bestored in a memory of the access point to improve performance when astation is assigned to another basic service serviced by the accesspoint.

After the assignment of the first and second client station, the firstand second basic service sets are serviced independently by the accesspoint at 320 by concurrently transceiving (transmitting or receiving)first data in a first wireless channel between the access point and thefirst client station and second data in a second wireless channelbetween the access point and the second client station.

As described above, in the concurrent servicing mode which may bereferred also as the multiple BSS mode, for each channel at least oneantenna is provided for transceiving the RF signals in the respectivechannel. The first and second channel may be within a same frequencyband, for example the 2.4 GHz band or the 5-5.8 GHz band. According toIEEE standards 802.11, the 2.4 GHz band ranging from 2.412 GHz to 2.462GHz is separated into eleven channels. In other standards, for exampleITU standards, the 2.4 GHz band from 2.412 to 2.472 GHz is divided inthirteen channels. From the available channels, two channels, forexample channels 1 and 11 or 1 and 6 are selected for the first andsecond channel. Selection of the first and second channels may take intoaccount a separation of the channels to avoid interference, for examplethe first and second channels may have a separation of at least 25 MHzwhich limits the number of channels available for the first and secondchannel.

In other embodiments, the first and second channels are selected fromdifferent bands. For example, one of the first and second channels isselected from the available frequency channels of the 2.4 GHz band whilethe other is selected from the available frequency channels of the 5 GHZband. Selecting the first and second channels from different bandsprovides an extended frequency separation and may relax constraints inthe RF processing due to closely located RF frequencies and resultinginterference.

While in the above exemplary operation a first and second client stationis assigned to a first and second basic service set, it is to be notedthat more than one client stations may be assigned to the first andsecond basic service sets. Furthermore, more than two basic service setsmay be serviced by the access point concurrently.

Assignment of the first and second stations and/or the other stationsmay be provided to improve or optimize the data communication for theplurality of client stations serviced by the access point and may beprovided in a dynamic manner. For example, by assigning stations todifferent basic service sets, throughput, QoS (Quality of Service) orrobustness of the wireless local area network may be improved oroptimized. To this end, the assignment of the client stations to a basicservice set may be provided based on the type of the data communicatedby the station, the Quality of Service assigned to the data communicatedby the station, the robustness of transmission expected for the datacommunication or a bandwidth (data throughput) required for the datacommunication of the station. The above criteria may be in accordancewith services or service classes provided by the various standards. Forexample IEEE 802.11 e/n classifies the data traffic into four accesscategories with different priorities for accessing the medium fortransmission. Typically, the highest priority access category isdedicated to VoIP traffic which consumes low bandwidth but tolerateslittle delay of only up to 30 msec. A second highest priority isprovided for video streams having a high bandwidth of up to 25 Mbps perstream but tolerable delays of up to 200 msec. The lower priority accesscategories are intended for non-real-time traffic, for exampledownloading of data files or browsing in the internet. In overloadsituations, for example when a high number of client stations areserviced in a basic service set or degrading channel conditions occur,the Quality of Service might not be met if the stations are servicedwithin a single basic service set. In these situations, the separationof the stations in different basic service sets provides improvement foreach of the services as the assignment can be based on the specificrequirements of the data traffic, such as high bandwidth or low latencyetc. For example, the first basic service set might be operatedaccording to IEEE 802.11n providing data transmission in spatial streams(MIMO) at a high bandwidth while the second basic service set operateswith reduced bandwidth in legacy mode (802.11g or 802.11b) but with lowlatency.

Other criteria according to which the assignment can be provided mayinclude the number of client stations assigned to the first basicservice set and the second basic service set, the current data networktraffic load in the first basic service set or the second basic serviceset or power saving requirements for a client station.

In one embodiment, the capabilities of the stations to operate inaccordance with specific transmission or operation modes may be used ascriteria for assigning the stations to the respective basic servicesets. For example, the IEEE 802.11n standard provides for twotransmission modes, a mixed transmission mode which allows support oflegacy WLAN standards such as IEEE 802.11a or 802.11g and a Greenfieldmode which is a “pure” 802.11n transmission mode without providingsupport of legacy WLAN standards. While the mixed mode uses a longerheader and requires the use of protection mechanisms, for exampleRTS/CTS- or CTS-to-self sequences in order to be backwards compatible,the Greenfield mode can use a simplified header, does not requireprotection and can therefore provide higher data throughput. Accordingto embodiments, both of the first and second first basic service setsmay be provided in mixed mode supporting legacy devices in each of thebasic service sets as shown in FIG. 4 a. In other embodiments, one ofthe basic service sets, for example the first basic service set may beprovided in a Greenfield mode while the second service set is operatedin mixed mode providing the support for legacy stations as shown in FIG.4 b. Assignment of a station to the first basic service set maytherefore be based on the capability of the client station to operate ina Greenfield mode, or in other words, on the capability to transmitaccording to IEEE 802.11n standard.

Furthermore, the assignment of the stations to the basic service setsmay according to embodiments be based on a security protection requiredfor the data communication of a given station.

It is further to be noted that the assignment may according to oneembodiment be based on a combination of two or more of the criteriadescribed above. Look-up tables or optimizing functions combined withmonitoring of the data traffic may be used in order to determine aconfiguration for the stations in the different basic service sets bestsuited for the current situation. It is to be noted that the servicingof the two or more different basic service sets as described can befully compliant with the existing WLAN standards like IEEE 802.11standards. For example, in accordance with existing standards, each ofthe first and second basic service sets may be identified by a basicservice set identifier (BSSID). The basic service set identifier may belinked to a MAC address provided by the manufacturer of thesystem/device which uniquely identifies the basic service set.

While the access point provides for each of the multiple basic servicesets an independent MAC address (BSSID), the access point itself stillappears outside of the WLAN, for example for the distribution system ora backbone system, as a single access point with a single interface forthe data connection out of the WLAN. In order to forward data packetscorrectly to the MAC path corresponding to the basic service set of thestation, the access point implements bridging functionality.

Bridging functionality may be provided in various ways. For example,according to one embodiment of an access point connected to an Ethernetdistribution system, the access point receives all data packetstransmitted on the Ethernet distribution system. The access point, i.e.the BSS controller entity of the access point, determines whether thedestination address of the received data packet corresponds with theaddress of one of the stations assigned to the first or second basicservice set. If the destination address matches the address of one ofthe stations, the data packet will be transferred to the MAC entityassociated with the basic service set to which the station is assigned.FIGS. 7 a and 7 b show an exemplary bridging operation for adistribution system in the single BSS servicing mode. In FIG. 7 a, adevice A coupled to an Ethernet distribution system 110 sends data to astation C serviced by the access point 102. For transmission on theEthernet distribution system, an Ethernet data packet is transmittedfrom device A to access point 102. The header of the Ethernet datapacket transmitted from device A to the access point 102 includes thedestination address DA which corresponds to the MAC address of thereceiver station C and a source address which corresponds to the MACaddress of the sender device A. At the access point 102, data packetstransmitted on the distribution system 110 are analysed to determinewhether the destination address matches one of the MAC addresses of thestations serviced by the access point 102. After determining that thedestination address of the data packet matches the MAC address ofstation C, access point 102 generates a WLAN data packet by translatingthe Ethernet header to a WLAN header. In the WLAN header, in addition tothe source and destination address, a transmitter address is included inthe WLAN header which corresponds to the BSSID of the basic service setserviced by the access point 102. The split between source address andtransmitter address is provided because the 802.11 MAC sendsacknowledgments to the frame's transmitter (the access point), butreplies are sent at higher layers to the frame's source.

In FIG. 7 b, station C sends data to device A. Station C transmits aWLAN data packet comprising WLAN header data. In the WLAN header data,the destination address is indicated to be the address of device A andthe source address SA is indicated to be the address of station C.Further, a receiver address RA is contained in the WLAN header. In theexample of FIG. 7 b, the station C is assigned to basic service set BSS1and therefore the receiver address RA corresponds to the BSSID of basicservice set BSS1. Access point 102 receives the WLAN data packet andgenerates an Ethernet packet by translating the WLAN header to anEthernet header. As already described, the Ethernet header contains onlysource and destination address. The Ethernet packet is then transmittedover distribution system 110 to device A.

Referring now to FIGS. 8 a and 8 b an exemplary operation of thebridging functionality in a distribution system is shown when the accesspoint 102 services multiple basic service sets. In the embodiment shownin FIGS. 8 a and 8 b, station C is assigned to the first basic serviceset BSS1 and station D is assigned to the second basic service set BSS2.When device A sends data to station C, device A transmits an Ethernetdata packet including the source address of device A and the destinationaddress of station C as already described with respect to FIG. 7 a.Access point 102 then analyses the data packet to determine whether thedestination address matches one of the addresses of the stationsassigned to basic services sets BSS1 or BSS2. If the destination addressmatches one of the stations, a WLAN data packet is generated andtransmitted to the stations via the basic service set to which thestation is assigned. The WLAN data packet is generated by introducinginto the WLAN header the transmitter address corresponding to the BSSIDof the basic service set to which the station is assigned, i.e. theBSSID of BSS1 or BSS2. In the example, station C is assigned to basicservice set BSS1 and therefore the transmitter address in the WLANpacket corresponds to the BSSID of the basic service set BSS1. Referringto FIG. 8 b, in the reverse direction when station C sends data todevice A, station C transmits a WLAN data packet to access point 102.The WLAN data packet comprises a WLAN header with a receiver addresscorresponding to the BSSID of basic service set BSS1. The access point102 receives the WLAN data packet from station C and generates anEthernet data packet. As described above, the Ethernet data packetcomprises the address and destination address but not the BSSID of thebasic service set. It will be noted by a person skilled in the art thatthe above operation corresponds to an extension of the bridgingfunctionality into the wireless media. The MAC address of the accesspoint itself will not appear in the Ethernet medium.

In another embodiment of an access point implemented in or connected toa gateway such as a DSL access gateway, the bridging functionality maybe provided as described above or may be provided already in the gatewayfor example by implementing the BSS controller entity as driver softwarerunning on a processor (CPU) of the gateway. With this implementation,the decision in which basic service set a data packet is transmitted andtherefore in which MAC path the data is further processed in the accesspoint is decided at the gateway.

While the stations have been assigned to the basic service set, thewireless local area network may be dynamically reconfigured by theaccess point 102 taking into account changes in conditions of thewireless local area network such as traffic load, data type of datapackets, the number of active stations etc.

The dynamic reconfiguration may include a reassigning of one or morestations to alternative basic service sets. According to embodiments,the reassigning may occur during normal data transmission operation. Forexample, the second client station may be reassigned to the first basicservice set thereby increasing the number of stations assigned to thefirst basic service set and decreasing the number of stations assignedto the second basic service set. This reassignment may for example beprovided when the first basic service set has available data transfercapacity while the second basic service set is near the data transfercapacity limit or for any other reasons.

Furthermore, reassignment may include switching from operating multiplebasic service sets to operating a single basic service set. Here, thereassignment of the second client station to the first basic service setimplies that the second basic service set is without any assigned clientstation. Then, the second MAC path and the second PHY path correspondingto the second basic service set may be deactivated and the access pointservices only a single basic service set. However, it is to be notedthat the RF capacity, i.e. the RF engines and the RF antennas may bereused for spatial multiplexing or for increasing the number of spatialstreams in spatial multiplexing in the servicing of a single basicservice set. Thus, by adding the one or more antennas and RF enginesprovided for servicing the second basic service set in the multiple BSSmode, the number of spatial streams can be increased in the single BSSmode as will be further described.

Furthermore, dynamic reconfiguration of the wireless local area networkmay include a reconfiguration of the first and second channel providedfor the first and second basic service set. For example, the widths ofthe frequency channels may be increased or switched to operation modeswhere a partial overlap of the frequency regions takes place. While inthe concurrent transmission mode the first and second channels arenon-overlapping allowing simultaneous transmission of RF signals forboth basic service sets, in this new overlapping or coexistence mode thesimultaneous transmission of the RF signals for both basic service setswould result in interferences between the basic service sets. Therefore,for better performance in the coexistence mode, the radiation of the RFsignals may be coordinated. Coordination of the RF signal radiation maybe provided in higher layers or higher levels of the hierarchy forexample by utilizing the BSS controller entity to coordinate theprocessing of the data in the first and second MAC entity and/or in thefirst and second PHY entity.

The dynamic reconfiguration may also include a switching to atransmission mode where two different transmission modes arealternating, for example, a phased coexistence operation (PCO) accordingto IEEE standard 802.11n. As described above, the BSS controlling entitymay allow coordination of the two alternating transmission modes. Forexample, in the phased coexistence operation, the access point operatesin two alternating phases. In the first phase, transmission is providedby a 20 MHz wide wireless channel (primary channel) and in the secondphase, transmission is provided by a 40 MHz wide channel consisting ofthe primary channel and a second 20 MHz wide channel (secondarychannel). According to one embodiment, which is illustrated in FIG. 9 b,the first basic service set is operating in phased coexistence mode andthe (primary) channel of the second basic service set is used assecondary channel for the first basic service set. The BSS controllerentity may provide coordination between the two MAC entities when toapply the 40 MHz phases for the first basic service set, thereby it canavoid interference and increase overall throughput. In the embodimentillustrated in FIG. 9 d, both of the basic service sets are operated inphased coexistence mode and the primary channel of one basic service setis used as secondary channel for the other basic service set, and viceversa. In this case the transmission may for example be coordinated suchthat a basic service set may switch to 40 MHz mode if no transmission isexpected during that time in the other basic service set. In anotherembodiment shown in FIG. 9 c, both of the basic service sets areoperated in phased coexistence mode and both basic service sets share acommon secondary channel. The transmission may for example becoordinated such that the two basic service sets are operated in the 40MHz mode in a complementary way (out-of-phase) such that at a given timeinstance only one of the basic service sets is transmitting at 40 MHzchannel width while the other basic service set is transmitting at 20MHz. Operation without phased coexistence is shown in FIG. 9 a.

It is to be noted that the operation of the access point as describedabove can be fully compliant with the existing standards. For example,the dynamic reassignment of the client stations may be provided by usinga protocol described in the IEEE standard 802.11k, i.e. the access pointcan send a neighbor report in one basic service set which lists theother basic service set as an alternative, and force a client station tobe reassigned by disassociating it from the current basic service set.This procedure is conform to existing standards. Furthermore, the accesspoint can force a station to be reassigned to a new basic service set bydisassociating the station from the present basic service set andthereby causing it to associate with the new basic service set byfollowing procedures provided in existing standards.

As already described above, towards the data port interface, the accesspoint can be regarded as a regular single access point. According toembodiments, the access point may be fully compliant with the standardsIEEE 802.11a/b/g/n and may therefore be fully interoperable with devicesoperating according to these standards.

As will be apparent to a person skilled in the art, many ways ofimplementing the servicing of the multiple basic service sets and thearchitecture described in FIG. 2 are possible. Exemplary implementationsutilizing MIMO (multiple input multiple outputs) spatial streaming willbe discussed now with respect to FIGS. 5 a to 5 d, 6 a and 6 b.

Referring to the embodiment according to FIG. 5 a, the RF signals in themultiple BSS servicing mode are radiated by providing for each of thefirst and second basic service set a single RF antenna. Each of the twoantennas is coupled via the RF engines in the multiple servicing mode toone of the PHY paths which is coupled to a corresponding MAC path asalready described with respect to FIG. 2. As shown in FIG. 5 b, theaccess point may then reconfigure the WLAN such that the access pointservices only a single basic service set. In the single BSS mode, theMAC entity corresponding to the second basic service set is deactivatedas indicated by a grey color. The first and second antennas used in themultiple BSS mode to radiate signals to each of the basic service setsare then combined to provide a 2×2 MIMO spatial multiplexing. Note thatthe PHY entities are now operating together and provide one logical PHYin order to provide the stream parsing and spatial mapping for the twochains required for the 2 MIMO-operated antennas. It can be seen thatthe above examples provide an efficient usage of the resources as theseparate PHY and RF engines can be used also for single BSS servicing inthe MIMO spatial multiplexing operation.

A further embodiment of a MIMO operation is shown in FIGS. 5 c and 5 d.In this embodiment, in the multiple BSS servicing operation, the firstchannel corresponding to the first basic service set operates in a MIMOoperation with 3 antennas provided by the access point thereby forming a3×n transmission network where n is the number of antennas at thereceiving client station. For example, if the client station receivingdata from the access point comprises 2 antennas as shown in FIG. 5 c, a3×2 MIMO communication system is formed in the direction from the accesspoint to one of the client stations. For each of the antennas, aseparate chain is provided in the RF engine and the baseband processingof the PHY entity as will be explained in more detail below.

Referring now to FIG. 5 d, the WLAN is reconfigured for a single basicservice set operation of the access point. The MAC entity correspondingto the second basic service set is deactivated and the second antenna iscombined with the first antennas to provide a MIMO spatial multiplexingwith 4 antennas. The PHY entities are combined in order to provide thestream parsing and spatial mapping of the four chains required foroperating the four antennas in MIMO spatial multiplexing.

While the embodiment according to FIGS. 5 c and 5 d provides a MIMOoperation with 3 antennas in the multiple BSS operation, it is to beunderstood that any integer number n1 (n1=2, 3, . . . ) of antennas canbe used for the MIMO operation. Furthermore, it is to be noted that inthe embodiment according to FIGS. 5 c and 5 d, also the second channelcan be operated in the multiple BSS operation in MIMO spatialmultiplexing with any number n2 of antennas. In the single BSSoperation, the n2 antennas can then be added to provide a MIMO spatialmultiplexing operation of up to N=n1+n2 antennas.

From the explanation of the above embodiments it becomes clear that anefficient utilization of the resources is provided as the separate PHYentities and RF engines can be used also for single BSS servicing in theMIMO spatial multiplexing operation.

A more detailed explanation of a baseband architecture corresponding tothe embodiment shown in FIGS. 5 c and 5 d will now be given withreference to FIGS. 6 a and 6 b.

FIG. 6 a shows a baseband architecture comprising a MAC block 702 and aPHY block 704. MAC block 702 and PHY block 704 may be implemented on asame chip or may be provided on different chips. The MAC implemented byMAC block 702 is divided into a Higher-MAC block for processing MACoperations on a higher hierarchical level which is implemented byrunning MAC software on a CPU 706 and a lower MAC block for processingMAC operations on a lower hierarchical level. The lower MAC block hastwo separate MAC instances 708 a and 708 b which are coupled to the CPU706 via a bus 710 and a crossbar 712. Crossbar 712 further allows theCPU to have access to a RAM 714, for example a SRAM, via a RAMcontroller 716.

Interfaces for providing the system interface for variousimplementations of the access point are further coupled to the Bus 710.For example, as shown in FIG. 6 a, an Ethernet interface 718 forallowing a system interface to a distribution system when the accesspoint is implemented for example in an extended service set is provided.Other bus interfaces which may be used for providing a system interfacefor example when the access point is implemented in a gateway mayinclude PCI or PCIexpress interfaces 720 and 722. In addition otherperipheral devices such as a DMA (direct memory access) controller 723may be coupled to the Bus 710.

In each of the lower MAC instances 708 a and 708 b, a Bus interface isprovided to allow access to Bus 710. A direct memory access device (DMAdevice) and RX-FIFO (Receive-First-In-First-Out) and TX-FIFO(Transmit-First-In-First-Out) buffers are provided in each MAC instance708 a, 708 b. In addition, functional blocks for address translationbetween WLAN (802.11) and Ethernet (802.3) andfragmentation/defragmentation are provided. In addition, each of thelower MAC instances 708 a and 708 b includes a crypto engine allowingcryptographic processing and a lower MAC block for providing otherlower-MAC functionality.

The PHY block 704 comprises a scrambler, encoder and stream parser block724 and a block 726 for providing STBC (Space time block coding) and/orbeamforming and/or MIMO operation. Space time block coding is atechnique used to improve data transmission by transmitting multiplecopies of the data distributed over several antennas and over time.

Data from the MAC instances 708 a and 708 b are provided to block 724for scrambling encoding and stream parsing. Four streams 732 areseparated by block 724 and provided to four RF chains 728 to support upto four spatial MIMO streams and four antennas. To transmit the basebandsignals to the RF engines for RF modulation a RF interface 730 isprovided which may be a digital or an analog interface. It is to benoted that the assignment of the RF chains to the MAC instances isconfigurable to allow in the single BSS operation STBC and/orbeam-forming and/or MIMO techniques such as spatial expansion and directmapping with up to four PHY chains and in the multiple BSS operationSTBC and/or beamforming and/or MIMO techniques with up to three PHYchains. Another configuration may include a data communication in themultiple BSS operation where the first and the second channel eachprovide two antennas for one of the above techniques or a combination ofthe above techniques. In this case, the system is configured to assigntwo PHY chains to the first MAC instance and two PHY chains to thesecond MAC instance.

FIG. 6 b shows data streams in the architecture of FIG. 6 a in amultiple BSS operation corresponding to the operation shown in FIG. 5 c.As can be seen, data from the first MAC instance 708 a are separatedinto three streams 732 a to 732 c and provided to block 726 for spacetime block encoding and spatial multiplexing. Data from the second MACinstance 708 b are provided in a fourth stream 732 d which istransferred to the corresponding RF chain without processing in the STBCand spatial mapping block 726, as the second channel is not operating inspatial multiplexing operation.

It is to be noted that the BSS controller entity is implemented in thisembodiment by running BSS controller software on the CPU 706. However,as described above, other implementations of the BSS controller entityin hardware, software or combinations thereof may be provided in otherembodiments as has already been outlined above.

In the above description, embodiments have been shown and describedherein enabling those skilled in the art in sufficient detail topractice the teachings disclosed herein. Other embodiments may beutilized and derived from this description, such that structural andlogical substitutions and changes may be made without departing from thescope of this disclosure. For example, while in the embodiments twobasic service sets serviced by the access point 102 have been described,it is to be understood that the access point 102 may service in otherembodiments more than two basic service set concurrently by more thantwo wireless channels.

This detailed Description, therefore, is not to be taken in a limitingsense, and the scope of various embodiments is defined only by theappended claims, along with the full range of equivalents to which suchclaims are entitled.

Such embodiments of the inventive subject matter may be referred toherein, individually and/or collectively, by the term “invention” merelyfor convenience and without intending to voluntarily limit the scope ofthis application to any single invention or inventive concept if morethan one is in fact disclosed. Thus, although specific embodiments havebeen illustrated and described herein, it should be appreciated that anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those skilled in theart upon reviewing the above description.

It is further to be noted that specific terms used in the descriptionand claims may be interpreted in a very broad sense. For example theterm “data” may be interpreted to include every form of representing thedata, such as an encrypted form of the data, an analog or digitalrepresentation, a modulated signal representing the data etc.Furthermore, the terms “circuit” or “circuitry” used herein are to beinterpreted in a sense not only including hardware but also software,firmware or any combinations thereof. Furthermore the terms “coupled” or“connected” may be interpreted in a broad sense not only covering directbut also indirect coupling.

The accompanying drawings that form a part hereof show by way ofillustration, and not of limitation, specific embodiments in which thesubject matter may be practiced.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment.

What is claimed is:
 1. An apparatus, comprising: a transceiver tosimultaneously transceive first data to a station associated with afirst basic service set, the first basic service set configured tosupport a mix of contemporary wireless standards and legacy wirelessstandards, and second data to a station associated with a second basicservice set, the second basic service set configured to support onlycontemporary wireless standards and to operate at a greater datathroughput than the first basic service set; a first MAC entity toprocess the first data and a second MAC entity to process the seconddata; and one or more first RF chains, the one or more first RF chainsbeing coupled to the first MAC entity and one or more second RF chains,the one or more second RF chains being coupled to the second MAC entity.2. The apparatus according to claim 1, further comprising a first MACentity to process the first data and a second MAC entity to process thesecond data.
 3. The apparatus according to claim 1, further comprisingan entity coupled to the one or more first RF chains, the entity beingcontrollable to process in a first operation mode only the first dataaccording to MIMO and/or STBC and/or beamforming techniques and toprocess in a second operation mode the first and the second dataaccording to MIMO and/or STBC and/or beamforming techniques.
 4. Theapparatus according to claim 1, further comprising a controller entityto control the data traffic to the first and second MAC entities,wherein the controller entity is configured to assign a first station toa first basic service set and a second station to a second basic serviceset.
 5. The apparatus according to claim 4, wherein the controllerentity is further configured to reassign the second station to the firstbasic service set and to control the transceiver to transceive thesecond data.
 6. The apparatus according to claim 4, wherein thecontroller entity is further configured to coordinate processing of thefirst data by the first MAC entity with the processing of the seconddata by the second MAC entity.
 7. An apparatus, comprising: a first portto receive data traffic comprising first and second data; a first MACcircuitry to process the first data, the first MAC circuitry configuredto support a mix of contemporary wireless standards and legacy wirelessstandards; a second MAC circuitry to process the second data, the secondMAC circuitry configured to support only contemporary wirelessstandards; a controller entity to control concurrent transferring of thefirst data to the first MAC circuitry and transferring of the seconddata to the second MAC circuitry, wherein the controller entity isfurther configured to assign a first client station to a first basicservice set and to assign a second client station to a second basicservice set, wherein the first data is associated with the first basicservice set and the second data is associated with the second basicservice set, and wherein the controller entity is further configured totransfer the first and second data based on the determined first andsecond basic service set, the second basic service set configured tooperate at a greater data throughput than the first basic service set;one or more first RF chains, the one or more first RF chains beingcoupled to the first MAC circuitry; and a second RF chain, the second RFchain being coupled to the second MAC circuitry.
 8. The apparatusaccording to claim 7, further comprising an entity coupled to the one ormore first RF chains, the entity being controllable to provide MIMOand/or STBC and/or beamforming processing in a first operation mode onlyfor the first data and to provide MIMO and/or STBC and/or beamformingprocessing in a second operation mode for the first and the second data.9. The apparatus according to claim 7, wherein the controller entity isfurther configured to reassign the second station to the first basicservice set and to transfer the second data to the first MAC circuitry.10. The apparatus according to claim 7, wherein the controller entity isfurther configured to coordinate processing of the first data by thefirst MAC circuitry with the processing of the second data by the secondMAC circuitry.
 11. A system, comprising an access point; and a firstwireless basic service set providing data transfer and a second wirelessbasic service set providing data transfer, wherein the first and secondwireless basic service sets are serviced by the access pointconcurrently and independent from the respective other wireless basicservice set, wherein the access point comprises a first MAC entity toprocess first data and a second MAC entity to process second data andwherein the first basic service set is configured to support a mix ofcontemporary wireless standards and legacy wireless standards and thesecond basic service set is configured to support only contemporarywireless standards and to operate at a greater data throughput than thefirst basic service set.
 12. The system according to claim 11, whereinthe access point further comprises a controller entity to control thefirst and second MAC entities, wherein the controller entity isconfigured to assign and reassign client stations to the first or secondbasic service set.
 13. A method comprising: assigning a first clientstation to a first basic service set serviced by an access point, thefirst basic service set configured to support a mix of contemporarywireless standards and legacy wireless standards; assigning a secondclient station to a second basic service set serviced by the accesspoint, the second basic service set configured to support onlycontemporary wireless standards and to operate at a greater datathroughput than the first basic service set; concurrently transceivingfirst data between the access point and the first client station andsecond data between the access point and the second client station,wherein concurrently transceiving the first and second data comprises:processing the first data in a first medium access controller (MAC)entity of the access point and processing the second data in a secondMAC entity of the access point, and transferring the first data to atleast one first radio frequency (RF) chain and transferring the seconddata to at least one second RF chain.
 14. The method according to claim13, wherein transceiving the first data comprises using a multipleinput, multiple output (MIMO) technique and/or a space time block coding(STBC) technique and/or a beamforming technique.
 15. The methodaccording to claim 13, further comprising reassigning the second clientstation to the first basic service set and, after reassigning the secondclient station, transceiving the second data to the second clientstation.
 16. The method according to claim 17, further comprisingreassigning the second client station to the first basic service set,wherein transceiving the first and second data after reassigning thesecond client station comprises transferring the first and second datato the plurality of first chains and the second RF chain fortransmitting the first and second data using a MIMO technique and/or aSTBC technique and/or a beamforming technique.
 17. The method accordingto claim 17, further comprising switching to a coexistence transceivingmode, wherein transceiving the first and second data in the coexistencetransceiving mode comprises coordinating the processing of the firstdata by the first MAC entity with the processing of the second data bythe second MAC entity.